Electro-optical device, manufacturing method thereof, and electronic apparatus

ABSTRACT

In an electro-optical device, a mirror and the like which is formed on an element substrate is sealed using a sealing member. The sealing member is provided with a frame section and a coyer section. In addition, the sealing member is provided on one face of the element substrate so that the mirror is surrounded by the element substrate and the sealing member and such that the mirror is positioned between a portion of the cover section and the element substrate. The sealing member is formed of a light-transmitting member having a frame section and a cover section which are integrally formed, and there is no interface between the frame section and the cover section.

The entire disclosure of Japanese Patent application No. 2015-063929,filed Mar. 26, 2015 is expressly incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention relates to a manufacturing method of anelectro-optical device which is provided with a mirror, theelectro-optical device, and an electronic apparatus.

2. Related Art

As an electronic apparatus, for example, a projection-type displaydevice and the like is known which displays an image cm a screen byenlarging and projecting modulated light using a projection opticalsystem after light which is emitted from a light source is modulated bya plurality of mirrors (micro mirrors) of an electro-optical devicereferred to as a digital mirror device (DHD). As shown in FIG. 12, theelectro-optical device which is used in the projection-type displaydevice and the like has an element substrate 1 which is provided with aplurality of mirrors 50 on one face 1 s side, and the mirror 50 issealed by a spacer 61 (sealing member) which is adhered to the one face1 s of the element substrate 1 so as to surround the mirror 50 and aplate-like light-transmitting cover 71 (sealing member) which is adheredto an end section on the opposite side to the element substrate 1 of thespacer 61.

As a method for manufacturing the electro-optical device, a method isproposed in which a second wafer, which is obtained by overlapping andadhering a spacer wafer with a through hole formed thereon and alight-transmitting wafer, is adhered to a first wafer on which themirror 50 is provided on one face 10 s side, and the first wafer and thesecond wafer are split (for example, refer to U.S. Pat. No. 6,856,014B1). According to the method, the spacer 61 is formed by the spacerwafer after splitting, and the light-transmitting cover 71 is formed bythe light-transmitting wafer after splitting.

However, according to the method described in U.S. Pat. No. 6,856,014B1, there is a problem in that it is not possible to avoid infiltrationof moisture via an interface of the spacer 61 and the light-transmittingcover 71 since the spacer 61 and the light-transmitting cover 71 areadhered to each other. The infiltration of moisture causes adsorption ofthe tilted mirror 50 to a member on the periphery thereof via waterdroplets when the mirror 50 is driven. The adsorption is not preferablesince the adsorption inhibits moving of the mirror 50 and the like.

SUMMARY

An advantage of some aspects of the invention is to provide anelectro-optical device which is able to prevent moisture infiltratingvia a sealing member with respect to a space in which a mirror isdisposed, a manufacturing method of the electro-optical device, and anelectronic apparatus.

An electro-optical device according to an aspect of the inventionincludes an element, substrate, a mirror which is provided on a firstface side of the element substrate, a driving element which is providedon the first face side of the element substrate and which drives themirror, and a light-transmitting sealing member which has a framesection and a cover section formed integrally with the frame section,and is provided on the first face side such that the mirror issurrounded by the sealing member and the element substrate, and themirror is positioned between a first portion of the cover section andthe element substrate.

In the aspect of the invention, the first face side of the elementsubstrate on which the mirror and the driving element are provided issealed by the light-transmitting sealing member, and the frame sectionwhich surrounds the mirror and the cover section which faces the mirrorare integral in the sealing member. For this reason, it is possible toprevent infiltration of moisture from between the frame section whichfunctions as a spacer and the cover section which functions as thelight-transmitting cover. Accordingly, when the mirror is driven, it isdifficult for a failure to occur in which it is not possible to move themirror due to adsorption of the tilted mirror to a member on theperiphery thereof via water droplets.

In the aspect of the invention, for example, the thickness of the coversection may be thicker than the thickness of the frame section.According to this configuration, it is possible to increase mechanicalstrength of the electro-optical device.

A manufacturing method of the electro-optical device according toanother aspect of the invention includes preparing a first wafer whichis provided with a first mirror and a first driving element that drivesthe first mirror in a first region on a first face side, and which isprovided with a second mirror and a second driving element that drivesthe second mirror in a second region which is adjacent to the firstregion on the first face side, forming a light-transmitting second waferwhich has a second face with a first concave section and a secondconcave section, adhering the first face of the first wafer and thesecond face of the second wafer such that the first mirror and the firstdriving element overlap with the first concave section in planar viewand such that the second mirror and the second driving element overlapwith the second concave section in planar view, and splitting the firstwafer and the second wafer along a region which overlaps with a regionthat is interposed by the first region and the second region in planarview.

In the manufacturing method of the electro-optical device according tothe aspect of the invention, it is preferable that a first groove isformed deeper than the first concave sect ion and the second concavesection in a region which is interposed by the first concave section andthe second concave section on the second face of the second wafer, inthe forming of the second wafer, and thinning of the second wafer isperformed in which the second wafer is split by thinning of the secondwafer over a region from a third face which is a face on an oppositeside to the second face of the second wafer to the first groove, in thesplitting. In this case, it is possible to split the second wafer into aplurality of pieces by one time of thinning of the second wafer unlike amethod in which the second wafer is split by a dicing blade.

In the manufacturing method of the electro-optical device according tothe aspect of the invention, the first groove may be formedsimultaneously with the first concave section and the second concavesection in a region which is interposed by the first concave section andthe second concave section on the second face of the second wafer, inthe forming of the second wafer, and dicing of the second wafer may beperformed in which the second wafer is split by a second wafer dicingblade being thrust to reach the first groove from a third face which isa face on an opposite side to the second face of the second wafer, inthe splitting.

In the manufacturing method of the electro-optical device according tothe aspect of the invention, it is preferable that the thickness of thesecond wafer dicing blade is thicker than the width of the first groove,and a cutting edge of the second wafer dicing blade is thrust to anintermediate position in a depth direction of the second groove beforethe dicing of the second wafer, in the dicing of the second wafer.According to this configuration, even in a case in which a bottomsection of the second groove is an arc-shaped concave section, it isdifficult for a convex section, which may cause a crack, to foe formedon a side face of the sealing member.

In the manufacturing method of the electro-optical device according tothe aspect of the invention, it is preferable that a second groove isformed in a region which is interposed by a first region and a secondregion on the first face of the first wafer before the splitting, andthinning of the first wafer is performed in which the first wafer issplit by thinning of the first wafer over a region from a fourth facewhich is a face on an opposite side to the first face of the first waferto the second groove, in the splitting. According to this configuration,it is possible to reduce a possibility of a crack being generated on arear face (fourth face) of the first wafer when the first wafer is splitby the dicing blade.

The electro-optical device to which the invention is applied is able tofoe used in various electronic apparatuses, and in this case, a lightsource section which irradiates the mirror with light from a lightsource is provided in the electronic apparatus. In addition, in a casewhere a projection-type display device is configured as the electronicapparatus, a projection optical system which projects light which ismodulated using the mirror is further provided in the electronicapparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic view illustrating an optical system of aprojection-type display device as an electronic apparatus to which theinvention is applied.

FIGS. 2A and 2B are explanatory views schematically illustrating a basicconfiguration of an electro-optical device to which the invention isapplied.

FIGS. 3A and 3B are explanatory views schematically illustrating a crosssection along line A-A′ in FIG. 2A of the main section of theelectro-optical device to which the invention is applied.

FIG. 4 is a sectional view of the electro-optical device to which theinvention is applied.

FIGS. 5A to 5D are sectional views illustrating a process in amanufacturing method of the electro-optical device to which theinvention is applied.

FIGS. 6A to 6D are diagrams illustrating a process in a manufacturingmethod of a second wafer or the like which is used in manufacture of theelectro-optical device to which the invention is applied.

FIGS. 7A to 7D are sectional views illustrating a process in a methodfor forming a concave section and a groove in the second wafer which isused in manufacture of the electro-optical device to which the inventionis applied.

FIGS. 8A to 8C are sectional views illustrating a sealing process of anelement substrate using a substrate and a sealing resin in themanufacture of the electro-optical device to which the invention isapplied.

FIGS. 9A to 9B are sectional views illustrating a process in anothermanufacturing method of the electro-optical device to which theinvention is applied.

FIGS. 10A and 10B are explanatory views illustrating a second waferdicing process in the other manufacturing method of the electro-opticaldevice to which the invention is applied.

FIGS. 11A and 11B are explanatory views illustrating a first wafersplitting process in yet another manufacturing method of theelectro-optical device to which the invention is applied.

FIG. 12 is a sectional view of an electro-optical device according to areference example of the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of the invention will be described with reference to thedrawings. Here, a projection-type display device will be described belowas an electronic apparatus to which the invention is applied. Inaddition, in the drawings described below, the scale of each layer andeach member is different in order for the sizes of each layer and eachmember to be to the extent so as to be recognizable in the drawings. Inaddition, the number of mirrors which are indicated in the drawings areset to be to the extent so as to be recognizable in the drawings, but alarger number of mirrors or the like than illustrated in the drawingsmay be provided. Here, in the embodiments below, for example, a casewhere “disposed on a first face side” is described, a case of disposingso as to come into contact with the first face, a case of disposing onthe first face via another construction, or a case of disposing aportion so as to come into contact with the first face and disposing theportion via another construction may be included.

Projection-Type Display Device as Electronic Apparatus

FIG. 1 is a schematic view illustrating an optical system of aprojection-type display apparatus as an electronic apparatus to whichthe invention is applied. A projection-type display device 1000 which isillustrated in FIG. 1 has a light source section 1002, anelectro-optical device 100 which modulates light which is irradiatedfrom the light source section 1002 according to image information, and aprojection optical system 1004 which projects the light which ismodulated by the electro-optical device 100 as a projection image onto aprojection target 1100 such as a screen. The light source section 1002is provided with a light source 1020 and a color filter 1030. The lightsource 1020 emits white light, the color filter 1030 emits light of eachcolor accompanying rotation, the electro-optical device 100 modulatesincident light at a timing synchronized with the rotation of the colorfilter 1030. Here, a fluorescent substrate which converts the lightemitted from the light source 1020 to light of each color may be used inplace of the color filter 1030. In addition, the light source section1002 and the electro-optical device 100 may be provided in each light ofeach color.

Basic Configuration of Electro-Optical Device 100

FIGS. 2A and 2B are explanatory views schematically illustrating a basicconfiguration of the electro-optical device 100 to which the inventionis applied, FIG. 2A is an explanatory view illustrating a main sectionof the electro-optical device 100, and FIG. 2B is an explodedperspective diagram of the main section of the electro-optical device100. FIGS. 3A and 3B are explanatory views schematically illustrating across section along line A-A′ in FIG. 2A of the main section of theelectro-optical device 100 to which the invention is applied, FIG. 3A isan explanatory-view schematically illustrating a state in which a mirroris tilted to one side, and FIG. 3B is an explanatory view schematicallyillustrating a state in which the mirror is tilted to another side.

As shown in FIGS. 2A to 3B, in the electro-optical device 100, aplurality of mirrors 50 are disposed in a matrix form on one face 1 s(first face) side of an element substrate 1, and the mirrors 50 areseparated from the element substrate 1. For example, the elementsubstrate 1 is a silicon substrate. For example, the mirror 50 is amicro-mirror in which one side length has a planar size of, for example,10 μm to 30 μm. For example, the mirror 50 is disposed with an arrayfrom 800×600 to 1028×1024, and one mirror 50 corresponds to one pixel ofan image.

A front face of the mirror 50 is an opposite face formed of a reflectivemetallic film of aluminum or the like. The electro-optical device 100 isprovided with a first level portion 100 a which includes a substrateside bias electrode 11, substrate side address electrodes 12 and 13, andthe like which are formed on the one face 1 s of the element substrate1, a second level portion 100 b which includes elevated addresselectrodes 32 and 33, and a hinge 35, and a third level portion 100 cwhich includes the mirror 50. On the first level portion 100 a, anaddress designating circuit 14 is formed on the element substrate 1. Theaddress designating circuit 14 is provided with a wire 15 or the like ofa memory cell, a word line, or a bit line for selectively controllingthe operation of each mirror 50, and has a circuit configuration whichis similar to a random access memory (RAM) which is provided with a CMOScircuit 16.

The second level portion 100 b includes the elevated address electrodes32 and 33, the hinge 35, and a mirror post 51. The elevated addresselectrodes 32 and 33 are supported by the substrate side addresselectrodes 12 and 13 while conducting to the substrate side addresselectrodes 12 and 13 via electrode posts 321 and 331. Hinge arms 36 and37 extend from both sides of the hinge 35. The hinge arms 36 and 37 aresupported by the substrate side bias electrode 11 while conducting tothe substrate side bias electrode 11 via an arm post 39. The mirror 50is supported by the hinge 35 while conducting to the hinge 35 via themirror post 51. Accordingly, the mirror 50 conducts to the substrateside bias electrode 11 via the mirror post 51, the hinge 35, the hingearms 36 and 37, and the arm post 39, and a bias voltage is applied fromthe substrate side bias electrode 11. Here, stoppers 361, 362, 371, and372 which prevent contact between the mirror 50 and the elevated addresselectrodes 32 and 33 are formed to abut with the leading ends of thehinge arms 36 and 37 when the mirror 50 is tilted.

The elevated address electrodes 32 and 33 configure a driving element 30which drives such that the mirror 50 is tilted by generatingelectrostatic force with the mirror 50. In addition, there are caseswhere the substrate side address electrodes 12 and 13 are alsoconfigured so as to drive such that the mirror 50 is tilted due toelectrostatic force being generated with the mirror 50, in this case,the driving element 30 is configured by the elevated address electrodes32 and 33 and the substrate side address electrodes 12 and 13. As shownin FIGS. 3A and 3B, in the hinge 35, a driving voltage is applied to theelevated address electrodes 32 and 33, the hinge 35 twists when themirror 50 is tilted so as to be pulled toward the elevated addresselectrode 32 or the elevated address electrode 33, and a force returningthe mirror 50 to a posture parallel to the element substrate 1 isexhibited when suction force is eliminated with respect to the mirror 50by stopping application of the driving voltage with respect, to theelevated address electrodes 32 and 33.

As shown in FIG. 3A, for example, in the electro-optical device 100, themirror 50 tilts to the elevated address electrode 32 side at one side,and an ON state is reached in which light which is emitted from thelight source section 1002 is reflected toward the projection opticalsystem 1004 by the mirror 50. In contrast to this, as shown in FIG. 3B,the mirror 50 tilts to the elevated address electrode 33 side at theother side, and an OFF state is reached in which light which is emittedfrom the light source section 1002 is reflected toward a light absorbingdevice 1005 by the mirror 50, and in the OFF state, the light is notreflected toward the projection optical system 1004. The driving isperformed for each of the plurality of mirrors 50, and as a result, thelight which is emitted from the light source section 1002 is modulatedto image light using the plurality of mirrors 50 and projected from theprojection optical system 1004, and an image is displayed.

Here, a yoke with a flat plate form which faces the substrate sideaddress electrodes 12 and 13 is integrally provided with the hinge 35,electrostatic force which is generated between the elevated addresselectrodes 32 and 33 and the mirror 50 is applied, and the mirror 50 isdriven by also using electrostatic force which acts between thesubstrate side address electrodes 12 and 13 and the yoke.

Structure of Electro-Optical Device 100

Seal Structure of Electro-Optical Device 100

FIG. 4 is a sectional view of the electro-optical device 100 to whichthe invention is applied. As shown in FIG. 4, in the electro-opticaldevice 100 of the embodiment, the element substrate 11 on which theplurality of mirrors 50 are formed which are described with reference toFIGS. 2A to 3B is sealed by a sealing member 25 in which the one face 1s has translucency, then is fixed to a substrate mounting section 93 ofa substrate 90, and then, is sealed using a sealing resin 98. In thesubstrate 90, the substrate mounting section 93 is a bottomed concavesection which is enclosed by a side plate section 32, and the elementsubstrate 1 is fixed using an adhesive 97 which is formed of a silverpaste or the like on a bottom plate section 91 of the substrate 90.

On the one face 1 s of the element substrate 1, a plurality of terminals17 are formed on end sections which do not overlap with the mirror 50 inplanar view (further outside a frame section 251). In the embodiment,the terminals 17 are disposed in two rows so as to interpose the mirror50. A portion of the plurality of terminals 17 are electricallyconnected to the elevated address electrodes 32 and 33 (driving element30) via the address designating circuit 14 and the substrate sideaddress electrodes 12 and 13 which are described with reference to FIGS.2A to 3B. Another portion of the plurality of terminals 17 areelectrically connected to the mirror 50 via the address designatingcircuit 14, the substrate side bias electrode 11, and the hinge 35 whichare described with reference to FIGS. 2A to 3B. Yet another portion ofthe plurality of terminals 17 are electrically connected to a drivingcircuit or the like which is provided at the front of the addressdesignating circuit 14 which is described with reference to FIGS. 2A to3B.

The terminal 17 is electrically connected by a wire 99 for wiringbonding to an internal electrode 94 which is formed on an inner face 91s on the element substrate 1 side of the bottom plate section 91 of thesubstrate 90. The bottom plate section 91 of the substrate 90 is amulti-layer substrate, and the internal electrode 94 conducts with anexternal electrode 96 which is formed on an outer face 91 t on a sideopposite to the element substrate 1 of the bottom plate section 91 via amulti-layer section 95 which is formed of a through hole and a wire thatare formed on the bottom plate section 91.

The sealing resin 98 is provided inside (in a concave section) of theside plate section 92 of the substrate 90. The sealing resin 98 coversthe wire 99, a joining section of the wire 99 and the terminal 17, ajoining section of the wire 93 and the internal electrode 94, around theelement substrate 1, a joining section of the element substrate 1 andthe sealing member 25 (frame section 251), and the side face of thesealing member 25 to the middle in a thickness direction.

Configuration of Sealing Member 25

In the embodiment, the sealing member 25 is provided with the framesection 251 (spacer) which surrounds around the mirror 50 and thedriving element (refer to FIGS. 2A to 3B), and a flat plate form coversection 252 which faces in an opposite direction to the elementsubstrate 1 in the mirror 50, and the end section on the elementsubstrate 1 side of the frame section 251 is adhered to the elementsubstrate 1. In this state, the cover section 252 faces the front faceof the mirror 50 at a position at intervals of a predetermined distancewith respect to the mirror 50 on the opposite side to the elementsubstrate 1. Here, the frame section 251 may surround the mirror 50 andthe driving element in planar view (in detail, in planar view whenviewed from the one face 1 s of the element substrate 1). In addition,by providing the sealing member 25 in this manner, the mirror 50 issurrounded by the sealing member 25 and the element substrate 1, and themirror 50 is positioned between a portion of the cover section 252(first section) and the element substrate 1.

In the embodiment, the sealing member 25 is formed of alight-transmitting member which is integrally formed with the framesection 251 and the cover section 252. For example, the sealing member25 is formed of a member made of glass which is integrally formed withthe frame section 251 and the cover section 252. For this reason, theframe section 251 and the cover section 252 are connected in series, andthere is no interface between the frame section 251 and the coversection 252.

In the electro-optical device 100 which is configured in such a manner,the light is incident onto the mirror 50 by penetrating the coversection 252, then the light which is incident at the mirror 50 isemitted so as to pass through the cover section 252. In the embodiment,the inside of the sealing member 25 adopts a configuration in whichthere is air, a configuration in which an inert gas and the like isfilled in place of air, or a configuration in which there is a vacuum.

In the embodiment illustrated in FIG. 4, although the thickness t of thecover section 252 and a thickness h1 of the frame section 251 are equal,it is preferable that the thickness t of the cover section 252 bethinner than the thickness h1 of the frame section 251. In addition, itis preferable that the thickness t of the cover section 252 be largerthan a distance h2 from a face which faces the element substrate 1 (orthe mirror 50) of the cover section 252 to a face which is adhered tothe element substrate 1 of the frame section 251. According to theconfiguration, in the electro-optical device 100 after sealing at thesubstrate 90, it is possible to increase mechanical strength of theentire electro-optical device 100 since it is possible to increase themechanical strength of the cover section 252 which is exposed. Theconfiguration is able to be realised by optimizing thickness in a secondwafer 20 which will be described later, the depth of a concave section21 and a groove 22, and the like.

Manufacturing Method of the Electro-Optical Device 100

The manufacturing method of the electro-optical device 100 to which theinvention is applied will be described with reference to FIGS. 5A to 8C.FIGS. 5A to 5D are process sectional views illustrating themanufacturing method for the electro-optical device 100 to which theinvention is applied. FIGS. 6A to 6D are process diagrams illustrating amanufacturing method of the second wafer 20 or the like which is used inmanufacture of the electro-optical device 100 to which the invention isapplied, and FIGS. 6A to 6D illustrate a cut end face view on a lowerlevel of a planar view while illustrating a planar view of a wafer ineach process. FIGS. 7A to 7D are process sectional views illustratingthe method for forming a concave section and a groove in the secondwafer 20 which is used in manufacture of the electro-optical device 100to which the invention is applied. FIGS. 8A to 8C are process sectionalviews illustrating sealing of the element substrate 1 using thesubstrate 30 and the sealing resin 98 in the manufacturing of theelectro-optical device 100 to which the invention is applied. In FIG.6B, illustration of the mirror and the like is omitted, in FIGS. 5A to5D and the like, illustration of the driving element 30 and the like isomitted, the number of mirrors 50 being reduced in comparison to FIG. 4and two mirrors 50 being formed on one element substrate 1.

In the embodiment, a plurality of element substrates 1 and the like froma wafer are collected. For this reason, out of the regions in which itis possible to obtain a plurality of element substrates 1 of the firstwafer 10, the mirror 50 and the driving element 30 which are formed in afirst region 101 are respectively described below as a first mirror 50 aand a first driving element 30 a. In addition, in the first wafer 10,the mirror 50 and the driving element 30 which are formed in a secondregion 102 which is adjacent to the first region 101 in which the firstmirror 50 a and the first driving element 30 a are formed will berespectively described as a second mirror 50 b and a second drivingelement 30 b. However, in a case where it is not necessary to specifywhether there is any element substrate 1, description will be madewithout attaching a or b.

As shown in FIGS. 5A and 5B, in the manufacture of the electro-opticaldevice 100 according to the invention, in the first wafer preparation,the first wafer 10 on which the driving element 30 (refer to FIGS. 2A to3B) is formed that drives the mirror 50 is prepared at a position whichoverlaps with the mirror 50 in planar view, while the mirror 50 isformed in each region in which the element substrate 1 is split withrespect to the one face 10 s (first face) of a large first wafer 10which can take a large number of the element substrates 1. On the oneface 10 s of the first wafer 10, the first driving element 30 a (referto FIGS. 2A to 3B) is formed at a position which overlaps with the firstmirror 50 a in planar view while the first mirror 50 a is formed in thefirst region 101. In addition, on the one face 10 s of the first wafer10, the second driving element 30 b (refer to FIGS. 2A to 3B) is formedat a position which overlaps with the second mirror 50 b in planar viewwhile the second mirror 50 b is formed in the second region 102. Inaddition, in the embodiment, a metal layer 170 is formed in order toform the terminal 17 so as to span the first region 101 and the secondregion 102. For example, as shown in FIGS. 5A, 6A, and 6B, the firstwafer 10 may be prepared by forming the driving element 30 (refer toFIGS. 2A to 3B) that drives the mirror 50 at a position which overlapswith the mirror 50 in planar view, while the mirror 50 is formed in eachregion in which the element substrate 1 is split with respect to the oneface 10 s of the large first wafer 10 which can take a large number ofthe element substrates 1.

As in FIGS. 5A, 6C, and 6D, in second wafer formation, the largelight-transmitting second wafer 20 which can take a large number ofsealing members 25 is prepared. In the embodiment, the second wafer 20is made of glass. On a second face 20 s which forms one face of thesecond wafer 20, the concave section 21 is formed in each region inwhich the sealing member 25 is split, and the concave section 21 is openat the second face 20 s. One out of a plurality of concave sections 21there is a first concave section 21 a, and the concave section 21 whichis adjacent to the first concave section 21 a is a second concavesection 21 b. Here, a depth d1 of the concave section 21 (concavesection 21 a and concave section 21 b) may be smaller than a thicknesst2 of the second wafer 20 at a location at which the concave section 21is formed.

In addition, in the embodiment, the bottomed groove 22 which surroundseach of the plurality of concave sections 21 is formed to extend in twodirections which intersect perpendicularly with each other on the secondface 20 s of the second wafer 20. Accordingly, one section of the groove22 extends along between the first concave section 21 a and the secondconcave section 21 b. In the embodiment, the groove 22 is formed to bedeeper than the concave section 21 (first concave section 21 a and thesecond concave section 21 b). That is, a depth d2 of the groove 22 isformed so as to be bigger than the depth d1 of the concave section 21(refer to FIG. 6D).

As shown in FIG. 7A, in the forming of the second wafer 20, for example,first, in a state in which a resist mask 270 is formed on the secondface 20 s of the second wafer 20, in etching which is illustrated inFIG. 7B, the concave section 21 (first concave section 21 a and thesecond concave section 21 b) is formed on the second face 20 s of thesecond wafer 20 by dry etching, or wet etching using a potassiumhydroxide solution. Next, as shown in FIG. 7C, after the resist mask 270is removed, as shown in FIG. 7C, the groove 22 is formed using a dicingblade 82. Here, after the groove 22 is formed, the concave section 21(first concave section 21 a and the second concave section 21 b) may beformed. In addition, the groove 22 and the concave section 21 (firstconcave section 21 a and the second concave section 21 b) may be formedby resist mask formation two times and etching two times. In addition,the groove 22 and the concave section 21 (first concave section 21 a andthe second concave section 21 b may be formed by stealth dicing using alaser.

Next, in adhesion as shown in FIG. 5B, the concave section 21 overlapswith the mirror 50 in planar view (for example, in planar view when thefirst wafer 10 is viewed from the one face 10 s), and the groove 22 isadhered to the one face 10 s of the first wafer 10 and the second face20 s of the second wafer 20 so as to overlap between the first region101 and the second region 102 in planar view. As a result, the firstconcave section 21 a overlaps with the first mirror 50 a and the firstdriving element 30 a in planar view, the second concave section 21 boverlaps with the second mirror 50 b and the second driving element 30 bin planar view, and the groove 22 overlaps with the metal layer 170which is formed between the first concave section 21 a and the secondconcave section 21 b in planar view. Accordingly, the metal layer 170 isnot adhered to the second wafer 20.

Next, in the splitting shown in FIGS. 5C and 5D, a laminated body 100 sis obtained with a single item size which is fixed by the sealing member25 overlapping with the element substrate 1 which is provided with themirror 50 by a laminated body 130 being split into the first wafer 10and the second wafer 20.

In the splitting, first, in thinning of the second wafer which isillustrated in FIG. 5C, the second wafer 20 is split by thinning of thesecond wafer 20 over a region from a third face 20 t which is a face onan opposite side to the second face 20 s of the second wafer 20 to thegroove 22. In further detail, the second wafer 20 is thinned and thesecond wafer 20 is split due to grinding of the third face 20 t of thesecond wafer 20 by a grinder 280. According to the configuration, it ispossible to split the second wafer 20 into a plurality of pieces in thethinning of the second wafer of one time in comparison to a method inwhich the second wafer 20 is split using a dicing blade.

Next, in the first wafer dicing which is illustrated in FIG. 5D, thefirst wafer 10 is diced along a region (a region which interposes thefirst region 101 and the second region 102) in which the elementsubstrate 1 is split in the first wafer 10 using a first wafer dicingblade 81. As a result, the first wafer 10 is split. At that time, thefirst wafer 10 becomes a terminal 17 by an electrode layer 170 beingcut. In the embodiment, the thickness of the first wafer dicing blade 81is thinner than the width of the groove 12. Accordingly, in the firstwafer dicing, the first wafer 10 is diced by the first wafer dicingblade 81 being caused to enter inside the groove 22 from a side of thesecond wafer 20 with respect to the first wafer 10.

As a result, a plurality of the electro-optical devices 100 aremanufactured on which the one face 1 s of the element substrate 1 onwhich a plurality of the mirrors 50 are formed is sealed by the sealingmember 25. As shown in FIG. 4, in a case where the electro-opticaldevice 100 is further sealed using the substrate 90 and the sealingresin 98, a process illustrated in FIGS. 8A to 8C is performed.

First, as shown in FIG. 8A, the substrate 90 which becomes a concavesection which is surrounded by the substrate mounting section 93 in theside plate section 92 is prepared, then, as shown in FIG. 8B, theelement substrate 1 is fixed to the bottom section of the substratemounting section 93 using the adhesive 97. Next, as shown in FIG. 8C,the terminal 17 of the element substrate 1 and the internal electrode 94of the substrate 90 are electrically connected by the wire 99 for wiringbonding. Next, as shown in FIG. 4, the sealing resin 98 is injectedinside the side plate section 92 of the substrate 90, then the sealingresin 98 is cured, and the element substrate 1 is sealed using thesealing resin 98. As a result, it is possible to obtain theelectro-optical device 100 on which the element substrate 1 is sealedusing the sealing member 25 (frame section 251 and cover section 252),the substrate 90 and the sealing resin 98.

Here, in the embodiment, a circular shape wafer is used, but a planarshape, a rectangular shape, and the like may be used.

Main Effects of Embodiment

As described above, in the electro-optical device 100 of the embodiment,the one face 1 s side of the element substrate 1 on which the mirror 50and the driving element 30 are provided is sealed by thelight-transmitting sealing member 25, and in the sealing member 25, theframe section 251 which surrounds around the mirror 50 and the drivingelement 30 and the flat plate form cover section 252 which faces themirror 50 are integral. For this reason, it is possible to preventinfiltration of moisture from between the frame section 251 whichfunctions as the spacer and the cover section 252 which functions as thelight-transmit ting cover. Accordingly, when the mirror 50 is driven, itis difficult for a defect to be generated in which it is not possible tomove the mirror 50 due to adsorption of water droplets to a member onthe periphery of the tilted mirror 50.

Other Manufacturing Method of Electro-Optical Device 160

FIGS. 9A to 9D are process sectional views illustrating anothermanufacturing method for the electro-optical device 100 to which theinvention is applied. FIGS. 10A and 10B are explanatory viewsillustrating dicing of the second wafer in the other manufacturingmethod for the electro-optical device 100 to which the invention isapplied.

In the embodiments above, the groove 22 is formed deeper than theconcave section 21 (first concave section 21 a and second concavesection 21 b), but as shown in FIG. 9A, the groove 22 may be formed withthe same depth as the concave section 21 (first concave section 21 a andsecond concave section 21 b). As shown in FIGS. 7A to 7C, the concavesection 21 (first concave section 21 a and second concave section 21 b)and the groove 22 are able to be formed at the same time by etching in astate in which the resist mask 270 is formed.

In this case, in adhesion as shown in FIG. 9B, the concave section 21overlaps with the mirror 50 in planar view, and the groove 22 is adheredto the one face 10 s of the first wafer 10 and the second face 20 s ofthe second wafer 20 so as to overlap between the first region 101 andthe second region 102 in planar view. As a result, the first concavesection 21 a overlaps with the first mirror 50 a in planar view, thesecond concave section 21 b overlaps with the second mirror 50 b inplanar view, and the groove 22 overlaps with the metal layer 170 whichis formed between the first concave section 21 a and the second concavesection 21 b in planar view. Accordingly, the metal layer 170 is notadhered to the second wafer 20.

Next, in the splitting process shown in FIGS. 9C and 9D, a laminatedbody 100 s is obtained with a single item size which is fixed by thesealing member 25 overlapping with the element substrate 1 which isprovided with the mirror 50 by a laminated body 130 being split into thefirst wafer 10 and the second wafer 20.

In the splitting, first, in the dicing of the second wafer which isillustrated in FIG. 9C, the second wafer 20 is split by the second waferdicing blade 82 being caused to enter from the third face 20 t side ofthe second wafer 20 reaching the groove 22.

Next, in the splitting, in the first wafer dicing which is illustratedin FIG. 9D, the first wafer 10 is diced by the first wafer dicing blade81 being caused to enter inside the groove 22 from a side of the secondwafer 20 with respect to the first wafer 10. As a result, a plurality ofthe electro-optical devices 100 are manufactured on which the one face 1s of the element substrate 1 on which a plurality of the mirrors 50 areformed is sealed by the sealing member 25.

In such a manufacturing method, it is preferable that a thickness W82 ofthe second wafer dicing blade 82 which is illustrated in FIG. 9C bethicker than a width W22 of the groove 22, and that a cutting edge ofthe second wafer dicing blade 82 be caused to enter up to anintermediate position in a depth direction of the second groove 22before dicing of the second wafer is performed. According to theconfiguration, as shown in FIG. 10A, even in a case in which a bottomsection 220 of the second groove 22 becomes an arc-shaped concavesection, it is difficult for a convex section to be generated such thata crack or the like is caused on a side face of the sealing member 25.That is, in a case where the bottom section 220 of the second groove 22becomes an arc-shaped concave section, as shown in FIG. 10B, when athickness W82 of the second wafer dicing blade 82 is thinner than thewidth W22 of the groove 22, a convex section 259 is generated on theside face of the sealing member 25. It is easy for the convex section259 to crack. In addition, when a crack is generated on the convexsection 259, the crack reaches the frame section 251 and the coversection 252, and in that case, the function of the sealing member 25 isreduced. However, according to the aspect which is illustrated in FIG.10A, since the convex section 259, which is a cause of the crack or thelike, is not easily generated, it is not easy for function reduction orthe like of the sealing member 25 to be generated.

Yet Another Manufacturing Method of Electro-Optical Device 100

FIGS. 11A and 11B are explanatory views illustrating a first wafersplitting process in yet another manufacturing method for theelectro-optical device 100 to which the invention is applied.

In the aspect which is described with reference to FIGS. 5A to 5D and 9Ato 9D, in the splitting which is illustrated in FIGS. 5D and 9D, thefirst wafer 10 is split by the first wafer dicing blade 81, but thefirst wafer 10 may be split using a dicing before grinding (DBG) method.In further detail, first, as shown in FIG. 11A, a groove 110 whichextends along a region which is interposed in each region (first region101 and second region 102) is formed on the one face 10 s of the firstwafer 10 before the splitting of the first wafer 10 is performed. InFIG. 11A, after the second wafer 20 is split, the aspect in which thegroove 110 is formed is illustrated, but the groove 110 may be formed ina process therebefore.

Then, in the splitting, as shown in FIG. 11B, the first wafer thinningis performed in which the first wafer 10 is split by thinning the firstwafer 10 over a region from another face 10 t (fourth face) which is aface on an opposite side to the one face 10 s of the first wafer 10 tothe groove 110. In further detail, the first wafer 10 is thinned and thefirst wafer 10 is split due to grinding of the other face 10 t of thefirst wafer 10 by a grinder 150. According to the configuration, it ispossible to reduce a concern of a crack being generated on the otherface 10 t of the first wafer when the first wafer 10 is split by thedicing blade.

What is claimed is:
 1. A manufacturing method of an electro-opticaldevice, comprising: preparing a first wafer which is provided with afirst mirror and a first driving element that drives the first mirror ina first region on a first face side, and which is provided with a secondmirror and a second driving element that drives the second mirror in asecond region which is adjacent to the first region on the first faceside; forming a light-transmitting second wafer which has a second facewith a first concave section, a second concave section and a firstgroove; adhering the first face of the first wafer and the second faceof the second wafer such that the first mirror and the first drivingelement overlap with the first concave section in planar view and suchthat the second mirror and the second driving element overlap with thesecond concave section in planar view; and splitting the first wafer andthe second wafer along a region between the first region and the secondregion in planar view, wherein the first groove is formed simultaneouslywith the first concave section and the second concave section, and isformed between the first concave section and the second concave sectionon the second face of the second wafer, and dicing of the second waferis performed in which the second wafer is split by a second wafer dicingblade being thrust to reach the first groove from a third face sidewhich is a face on an opposite side to the second face of the secondwafer, in the splitting of the first wafer and the second wafer.
 2. Themanufacturing method of the electro-optical device according to claim 1,wherein the first groove is formed deeper than the first concave sectionand the second concave section in the region which is interposed by thefirst concave section and the second concave section on the second faceof the second wafer, in the forming of the second wafer, and thinning ofthe second wafer is performed in which the second wafer is split bythinning of the second wafer over a region from a third face which isthe face on an opposite side to the second face of the second wafer tothe first groove, in the splitting of the first wafer and the secondwafer.
 3. The manufacturing method of the electro-optical deviceaccording to claim 1, wherein a thickness of the second wafer dicingblade is thicker than a width of the first groove, and a cutting edge ofthe second wafer dicing blade is thrust to an intermediate position in adepth direction of the first groove before the dicing of the secondwafer, in the dicing of the second wafer.
 4. A manufacturing method ofan electro-optical device, comprising: preparing a first wafer which isprovided with a first mirror and a first driving element that drives thefirst mirror in a first region on a first face side, and which isprovided with a second mirror and a second driving element that drivesthe second mirror in a second region which is adjacent to the firstregion on the first face side; forming a light-transmitting second waferwhich has a second face with a first concave section and a secondconcave section; adhering the first face of the first wafer and thesecond face of the second wafer such that the first mirror and the firstdriving element overlap with the first concave section in planar viewand such that the second mirror and the second driving element overlapwith the second concave section in planar view; and splitting the firstwafer and the second wafer along a region between the first region andthe second region in planar view, wherein a second groove is formed inthe region between the first region and the second region on the firstface of the first wafer before the splitting, and thinning of the firstwafer is performed in which the first wafer is split by thinning of thefirst wafer over a region from a fourth face which is a face on anopposite side to the first face of the first wafer to the second groove,in the splitting of the first wafer and the second wafer.